Mice homozygous for the spontaneous recessive small roller mutation can usually be identified by 2 weeks of age by their difficulty in walking, which persists into adulthood. The hind legs splay, the gait has a severe side-to-side sway with the body held lower than normal, and homozygotes often tumble over. They have difficulty righting. Homozygotes are also smaller than normal, half normal size at wean age and growing to three quarters normal size as adults. Homozygous females have smaller than normal litter sizes, often produce fewer than expected numbers of homozygotes, and have a high number of stillborn and lost newborns. Heterozygous intercrosses also produce a high number of stillborn and lost newborns. Male homozygotes might not be fertile.
The small roller mutation arose spontaneously in the CXB10/HiAJ recombinant inbred strain at The Jackson Laboratory when that strain was at generation F59. This mutant subline has been maintained by sibling inbreeding on this background ever since.
|Allele Name||small roller|
|Gene Symbol and Name||Cacna1a, calcium channel, voltage-dependent, P/Q type, alpha 1A subunit|
|Strain of Origin||CXB10/HiAJ|
|Molecular Note||This spontaneous mutation has a an extra G inserted in the coding region of Cacna1a in the poly(G) stretch at coding nucleotides 106-110 of the cDNA (NM_001252060).|
Due to the fragility and diminutive size of homozygous pups meal should be placed within easy reach and weaning should be delayed beyond the usual three week wean age. Homozygous females will breed, but have reduced litter size and increased stillborn and pre-wean death of pups. Homozygous males have not been found to breed. This strain can be maintained through progeny tested heterozygotes.
When using the CXB10/HiAJ-Cacna1asmrl/GrsrJ mouse strain in a publication, please cite the originating article(s) and include JAX stock #016887 in your Materials and Methods section.